A conventional electric dust collector is shown in Japanese Utility Model Publication No. 3021572 by way of example. That is, a metallic beam crosses above the exit of an exhaust pipe, the exhaust pipe having a metallic pipe whose interior surface lined with refractory matter. On approximately the center line of the exhaust pipe, a discharge electrode is hung from the crossbeam into the exhaust pipe so that it is electrically insulated from the exhaust pipe. A high DC voltage is applied between the discharge electrode and the metallic pipe through the crossbeam, whereby dust is collected at a high temperature from exhaust gases passing through the exhaust gases.
Practically the conventional high-temperature type electric dust collector, however, has restrictions on the operating voltage of a high-tension power supply. For this reason, when the diameter of the exhaust pipe is large, the electric field between the exhaust pipe and the discharge electrode cannot be increased to infinity. As a result, there is a possibility that the smoke dust flowing along the central portion of the exhaust pipe will pass through the exit of the exhaust pipe without being guided to the pipe exterior surface of a dust-collecting electrode. For this reason, the conventional high-temperature type electric dust collector lengthens the axial length of the dust collecting section of the exhaust pipe to eliminate the aforementioned disadvantage. However, since the exhaust pipe lengthens, there is a problem that the production cost will increase.
The present invention has been made in view of the aforementioned problems. Accordingly, it is an object of the present invention to provide an electric dust collector and an incinerator that are capable of enhancing collection efficiency without lengthening the dust collecting section of an exhaust pipe.